Diabetes mellitus is a chronic metabolic disorder caused by an inability of the pancreas to produce sufficient amounts of insulin so that the subject metabolism is unable to provide for the proper absorption of sugar and starch. This failure leads to hyperglycemia, i.e. the presence of an excessive amount of analyte within the blood plasma. Persistent hyperglycemia has been associated with a variety of serious symptoms and life threatening long term complications such as dehydration, ketoacidosis, diabetic coma, cardiovascular diseases, chronic renal failure, retinal damage and nerve damages with the risk of amputation of extremities. Because healing is not yet possible, a permanent therapy is necessary which provides constant glycemic control in order to always maintain the level of blood analyte within normal limits. Such glycemic control is achieved by regularly supplying external drugs to the body of the patient to thereby reduce the elevated levels of blood analyte.
An external biologically effective drug (e.g., insulin or its analog) was commonly administered by means of multiple, daily injections of a mixture of rapid and intermediate acting drug via a hypodermic syringe. While this treatment does not require the frequent estimation of blood analyte, it has been found that the degree of glycemic control achievable in this way is suboptimal because the delivery is unlike physiological drug production, according to which drug(s) enters the bloodstream at a lower rate and over a more extended period of time. Improved glycemic control may be achieved by the so-called intensive drug therapy which is based on multiple daily injections, including one or two injections per day of a long acting drug for providing basal drug and additional injections of a rapidly acting drug before each meal in an amount proportional to the size of the meal. Although traditional syringes have at least partly been replaced by drug pens, the frequent injections are nevertheless very inconvenient for the patient, particularly those who are incapable of reliably self-administering injections.
Substantial improvements in diabetes therapy have been achieved by the development of the drug delivery device, relieving the patient of the need for syringes or drug pens and the administration of multiple, daily injections. The drug delivery device allows for the delivery of a drug in a manner that bears greater similarity to the naturally occurring physiological processes and can be controlled to follow standard or individually modified protocols to give the patient better glycemic control.
In addition, delivery directly into the intraperitoneal space or intravenously can be achieved by drug delivery devices. Drug delivery devices can be constructed as an implantable device for subcutaneous arrangement or can be constructed as an external device with an infusion set for subcutaneous infusion to the patient via the transcutaneous insertion of a catheter, cannula or a transdermal drug transport such as through a patch. External drug delivery devices are mounted on clothing, hidden beneath or inside clothing, or mounted on the body and are generally controlled via a user interface built-in to the device or on a separate remote device.
Drug delivery devices have been utilized to assist in the management of diabetes by infusing drug or a suitable biologically effective material into the diabetic patient at a basal rate with additional drug or “bolus” to account for meals or high analyte values, levels or concentrations. The drug delivery device is connected to an infuser, better known as an infusion set by a flexible hose. The infuser typically has a subcutaneous cannula, adhesive backed mount on which the cannula is attached thereto. The cannula may include a quick disconnect to allow the cannula and mount to remain in place on the skin surface of the user while the flexible tubing is disconnected from the infuser. Regardless of the type of drug delivery device, blood analyte monitoring is required to achieve acceptable glycemic control. For example, delivery of suitable amounts of drug by the drug delivery device requires that the patient frequently determines his or her blood analyte level and manually input this value into a user interface for the external pumps, which then calculates a suitable modification to the default or currently in-use drug delivery protocol, i.e. dosage and timing, and subsequently communicates with the drug delivery device to adjust its operation accordingly. The determination of blood analyte concentration is typically performed by means of an episodic measuring device such as a hand-held electronic meter which receives blood samples via enzyme-based test strips and calculates the blood analyte value based on the enzymatic reaction.
In recent years, continuous analyte monitoring has also been utilized with drug delivery devices to allow for greater control of the drug(s) being infused into the diabetic patients. In addition to glucose monitoring, people with diabetes often have to perform drug therapy such as, for example, insulin dosing. People with diabetes may self-administer insulin to reduce their glucose concentration. There are a number of mechanical devices currently available which enable an individual to dose a predetermined quantity of insulin such as, for example, a hypodermic syringe, an insulin pen, and an insulin pump. One such insulin pump is the Animas® Ping, a product which is manufactured by Animas Corporation. Another is the Animas® Vibe, also manufactured by Animas Corporation.
People with diabetes should maintain tight control over their lifestyle, so that they are not adversely affected by, for example, irregular food consumption or exercise. In addition, a physician dealing with a particular individual with diabetes may require detailed information on the individual's lifestyle to provide effective treatment or modification of treatment for controlling diabetes. Currently, one of the ways of monitoring the lifestyle of an individual with diabetes has been for the individual to keep a paper logbook of their lifestyle. Another way is for an individual to simply rely on remembering facts about their lifestyle and then relay these details to their physician on each visit.
The aforementioned methods of recording lifestyle information are inherently difficult, time consuming, and possibly inaccurate. Paper logbooks are not necessarily always carried by an individual and may not be accurately completed when required. Such paper logbooks are small and it is therefore difficult to enter detailed information requiring detailed descriptors of lifestyle events. Furthermore, an individual may often forget key facts about their lifestyle when questioned by a physician who has to manually review and interpret information from a hand-written notebook. There is no analysis provided by the paper logbook to distill or separate the component information. Also, there are no graphical reductions or summary of the information. Entry of data into a secondary data storage system, such as a database or other electronic system, requires a laborious transcription of information, including lifestyle data, into this secondary data storage. Difficulty of data recordation encourages retrospective entry of pertinent information that results in inaccurate and incomplete records.
Recognizing these deficiencies, LifeScan Inc., has invented a diabetes management technique that utilizes statistical analyses, for example, a chi-squared test, to ensure the robustness of the glucose measurements. The technique is shown and described in U.S. patent application Ser. No. 11/688,639, now allowed, which is hereby incorporated by reference into this application as if fully set forth herein.